Endarterectomy apparatus

ABSTRACT

AN APPARATUS AND METHOD FOR REMOVING ARTERIOSCLEROTIC MATERIAL FROM AN ARTERY. AN ELECTRIC MOTOR IS CONNECTED BY FLEXIBLE SPRINGS OR TORQUE SHAFT TO A ROTATION OSCILLATION CONVERTER. A ROD HAVING A BENDABLE LOOPED TIP OR LOOP AT ITS DISTAL END IS REMOVABLY CONNECTED TO THE OSCILLATORY OUTPUT OF THE CONVERTER. THE LOOP OR TIP IS INSERTED INTO THE ARTERY WHICH HAS BEEN CUT TO RECEIVE THE TIP. THE TIP IS OSCILLATED BETWEEN THE MEDIA LAYER AND ADVANTITIA LAYER STRETCHING THE ADVENTITIA LAYER AND CAUSING SEPARATION OF THE TWO LAYERS. THE LOOSENED ARTERIOSCLEROTIC CORE IS THEN REMOVED INTACT FROM THE ARTERY WHICH IS THEN SURGICALLY CLOSED.   D R A W I N G

United States Patent 1 Lerwick et al.

[ j ilfii 1 ENDARTERECTOMY APPARATUS [22] Filed: Nov. 9, 1970 [21] Appl. No.: 87,902

[52] US. Cl 128/303, 74/25, 74/48, 128/304, 128/326, 128/356, 128/305 [51] Int. Cl A6lb 17/00 [58] Field of Search 128/303, 304, 305, 128/328, 356; 27/21, 24 R; 15/104.05; 74/25,'47, 48, 70, 89

[56] References Cited UNITED STATES PATENTS 1,561,935 11/1925 Kessler 74/70 UX 2,439,262 4/1948 Nalbach et al 74/48 3,472,081 10/1969 Keller et a1. 74/48 2,372,930 4/1945 Bovee 128/303 R 2,868,206 l/1959 Stoesser 128/303 R 2,917,762 12/1959 Xenis 15/104.05

2,944,552 7/1960 Cannon 128/304 3,446,666 5/1969 Bodine 15/104105 X FOREIGN PATENTS OR APPLlCATlONS 95,880 l/l924 Austria 128/303 362,997 11/1922 Germany 128/304 Primary Examiner-Aldrich F. Medbery Attorney-Woodard, Weikart, Emhardt & Naughton [57] ABSTRACT An apparatus and method for removing arteriosclerotic material from an artery. An electric motor is connected by flexible springs or torque shaft to a rotation oscillation converter. A rod having a bendable looped tip or loop at its distal end is removably connected to the oscillatory output of the converter. The loop or tip is inserted into the artery which has been cut to receive the tip. The tip is oscillated between the media layer and advantitia layer stretching the adventitia layer and causing separation of the two layers. The loosened arteriosclerotic core is then removed intact from the artery which is then surgically closed.

3 Claims, 9 Drawing Figures PMENTELHmz 1 m4 sum 1 BF 3 Fig.1. V

INVENTORS WILLIAM A fvsem-r R [MW/me BY MM MM M1;

ATTORNEYS PATENTEBMAY 2 1 1914 "saw 2 or 3 INVENTORS WILL/AM [50k EVERETT LE/QW/CK BY v aim/M1 Mahmud fmfiii ATTORNEYS ENDARTERECTOMY APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a surgical method and apparatus and more specifically to method and apparatus for removing arteriosclerotic material from an artery.

2. Description of the Prior Art Many deaths have been caused by reduced flow of blood through an artery which is blocked when the intima and media layers thicken. Calcified soft deposits collect within the artery passage further retarding the flow of blood. Heretofore, the material blocking the artery passage has been partially removed by various cutting techniques, by gas or by a vibratory catheter, such as the one disclosed in the U. S. Pat. No. 3,433,226 issued to Boyd. This latter device destroys the calcified atheromata, which is then flushed away. The principle of endarterectomy heretofore utilized has been based on the principle of removing the atheromatous core from the inside of the adventitial tube of the artery. There was never any definite attempt to open the collateral vessels branching from the main occluded arterial trunk. The prior principle was to remove the occluding core, leaving an open conduit for the arterial blood to pass through the adventitial tube to the distal extremity.

The present invention is quite different from the prior art in that it does not involve cutting the material from the artery nor does it utilize vibration to destroy the material. Instead, an oscillating loop is used to stretch and loosen the adventitia layer from the media layer of the artery. The media and intima layers along with the calcified deposits blocking the artery passage are then pulled from the artery.

The concept using the oscillating endarterectomy disclosed herein is based on the principle of removing the adventitial tube from the underlying sclerotic core and in doing so to open the collateral vessels. The adventitial tube is lifted off from the underlying core allowing the removal of the small spicules that protrude from the main occluding core into the collateral vessels. When the small spicules are removed from the orifices of the collateral vessels, the collaterals once again function in a normal manner and a major segment of the circulatory tree is returned to normal. In order to accomplish this concept an oscillating loop is used which passes through the plane between the adventitia and media and actually stretches the adventitia away from the underlying core as the loop is passed proximally or distally into the arterial tree. The instrument has been used to endarterectomize the superficial femoral artery, the popliteal artery, the anterior tibial artery and the posterior tibial artery as low as the ankle.

SUMMARY OF THE INVENTION One embodiment of the structure of this invention might include an apparatus for removing arteriosclerotic material from a body vessel comprising a rod having an axis and a proximal end and a distal end; means secured to the proximal end of said rod for oscillating said rod about its axis; and a looped tip secured to the distal end of said rod.

One embodiment of the method of this invention might include a method of removing arteriosclerotic material from an artery which comprises the steps of: opening the artery by incision; transecting the medial core of the artery; placing a loop between the medial core and the adventitial tube; oscillating the loop and simultaneously advancing the loop up the artery between the medial core and the adventitial tube to stretch the adventitial tube and separate it from the medial core; and, removing the medial core intact from the adventitial tube.

It is one object of this invention to provide improved method and apparatus for opening clogged arterial passages.

It is a further object of the present invention to provide method and apparatus for opening clogged arterial passages without cutting the clogging material from the artery or without destroying the clogging material by vibration.

Related objects and advantages will be apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary view of the endarterectomy apparatus of the present invention.

FIG. 2 is an enlarged sectional view of converter 30 shown in FIG. 1' taken along the line 2-2 and viewed in the direction of the arrows.

FIG. 3 is a perspective view of converter 30 with a portion of the outer housing broken away.

FIG. 4 is an enlarged perspective view of rod shown in FIG. 1.

FIG. 5 is a fragmentary view of an artery.

FIG. 6 is an enlarged cross sectional view of the artery of FIG. 5 taken along the line 6-6 and viewed in the direction of the arrows.

FIG. 7 is an enlarged end elevation of a rod forming a part of the structure illustrated in FIG. 1.

FIG. 8 is an enlarged view similar to FIG. 6 of a further step in the method of the invention.

FIG. 9 is a view similar to FIG. 8 of a subsequent step in the method of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT scope of the invention is thereby intended, such alterations and further. modifications in the illustrated device and such further applications of the principles of the invention as illustrated herein being contemplated as would normally occur to one skilled in the art to which the invention relates.

FIG. 1 is a fragmentary view of the endarterectomy apparatus 10 incorporating the present invention. Apparatus 10 has a converter 30 for translating the rotational motion produced by electric motor I 1 into an oscillatory motion of rod 70. Motor 1 1 has a conventional input power line 12 and a foot control rheostat 14 for controlling the rotational motion of output coupling 15. Rheostat 14 is electrically connected to motor 11 by cable 13 and is commercially available from the Electrical Manufacturing Company of Chicago, Illinois, under Model No. 6000. This same control rheostat is disclosed in U. S. Pat. No. 2,988,720. A flexible outer helical spring 16 encloses an inner helical spring 17. Spring 16 is broken away to more clearly illustrate spring 17. Spring 17 has four wires 19, 20, 21 and 22 (FIG. 2) helically wound adjacent each other extending from plug 18 to converter 30 (FIG. 1). Springs 16 and 17 are fixedly fastened to plug 18 by brazing or other suitable means. Plug 18 has an outside diameter Slightly less then the inside diameter of coupling and has a key insertable into a keyway formed in the inner periphery of coupling 15. A conventional ball lock is provided in coupling 15 to securely lock plug 18 therein. Thus, plug 18 and springs 16 and 17 will rotate directly with coupling 15.

Converter is held in the surgeons hand receiving the rotational motion of springs 16 and 17 and converting the motion to an oscillatory motion of rod 70. Converter 30 has two outer housings 32 and 31 enclosing the mechanism for producing the oscillatory motion. FIG. 2 is an enlarged cross sectional view of converter 30 taken along the line 22 of FIG. 1 and viewed in the direction of the arrows. The converter 30 also serves as a handle for the surgeon to hold the apparatus while in use. FIG. 3 is a perspective view of the converter with housings 31 and 32 partially broken away.

Referring now to FIGS. 2 and 3, springs 16 and 17 are fixedly fastened by brazing or other suitable means to input shaft 36 having hole 37 at its opposite end for receiving shaft 40. Set screw 38 is threadedly received by shaft 36 abutting against flat side 41 of shaft securely locking the two shafts together. Shaft 40 is integrally connected to shaft 43 which is rotatably mounted to bushing 64. Channel 44 is provided in shaft 43 receiving lock washer 45 which will abut surface 28 in the event that shaft 43 is forced in the direction of arrow 27. Shaft 40 is provided with shoulder 42 which prevents shaft 43 from moving in a direction opposite to arrow 27. Bushing 64 threadedly receives housing 32 at Y 65 providing an enclosure for shafts 36 and 40. Retaining ring 68 integrally joined to rib 66 is fitted over the shouldered end 67 of bushing 64.

Fasteners 69 are threadedly received into bushing 64 securing ring 68 and bushing 64 together. Housing 31 is fitted over ring 68 and rib 66 abutting housing 32. Set screws 33 are threaded through housing 31 abutting against shoulder 67 of bushing 64. Set screws 33 are positioned around the circumference of housing 31 in an adequate number to secure housing 31 and bushing 64 together. A plastic rotary coupling 47 is fixedly secured to shaft 43 by serrations on the outer surface of shaft 43 up to end 46. A second shaft 49 is fixedly fastened to coupling unit 47 by serrations on its outer surface 48. A counterweight 24 is mounted in the opposite end of coupling 47. Shaft 49 has a ball 50 integrally attached to one end, freely slidable in slot 54 of center coupling 52. Thus, as shaft 43 rotates, ball 50 will move back and forth in the direction of arrow 80. Center coupling 52 is freely mounted by fastener 51 threadedly received by rib 66. Member 52 has wings 53 and positioned on either side of fastener 51. Wing 53 has slot 54 slidably receiving ball 50, whereas wing 55 has slot 56 slidably receiving ball 57 of shaft 58.

Elbow coupling is fixedly fastened to shaft 58 by serrations provided on the outer surface 59 of shaft 58 and is connected to output shaft 61.

Lock washer 63 is fitted into channel 62 of shaft 61 to prevent coupling 60 and shaft 61 from becoming disengaged. Shaft 61 is keyed to coupling 60 to prevent relative motion between coupling 60 and shaft 61. Cylinder 82 is integrally attached to rib 66 having a stepped end 87. A conventional rubber boot 34 encirii i ,446

cling shaft 61 is mounted between stepped end 87 and housing 25, fixedly secured to housing 31 by brazing or other suitable means. Cylinder 82 is hollow and receives bushing 83. Shaft 61 extends freely through bushing 83.

A lock washer 86 is mounted in channel 88 of shaft 61 adjacent to fiber washer 85. Holder 35 having a square cross section is integrally attached to shaft 61 and is receivable into the hollow interior 91 (FIG. 4) of body 90. Fastener 89 is threadedly received by body 90 and extends into interior 91 for abutting against holder 35. Thus, a variety of different sized rods and tips 72 may be coupled to holder 35. A hollow rod 70 is fixedly attached to body by brazing. The opposite end of rod 70 receives and is brazed to a loop or a looped wire tip 72 which defines hole 71. Tip 72 is bendable and thus hole 71 may be configured in various shapes. In addition, tip 72 forms an angle 73 of 45 between the plane defined by the loop and the axis of the rod 70 (FIG. 1). Best results are obtained by using soft annealed stainless steel wire for the loop 72. Rod 70 is a hardened stainless steel hypodermic tube.

Upon activation of motor 11, springs 16 and 17 will rotate along with shafts 36 and 43. Rotary coupling 47 will rotate with shaft 43 forcing ball 50 to move back and forth in the direction of arrows 80 in slot 54. In addition, ball 50 will cause center coupling 52 to oscillate about fastener 51 in the direction of arrows 81 (FIG. 3). Wing 55 will be forced to pivot about fastener 51 pulling ball 57 along the pivotal path. Thus, elbow coupling 60 will oscillate along with rod 70. In one embodiment of the present invention, one revolution of springs 16 and 17 caused rod 70 to oscillate through an angle of approximately 120 although angles of something less than 360 are workable. This same embodiment oscillated rod 70 up to 8,000 oscillations per minute.

FIG. 6 is a cross section of artery of FIG. 5. The walls of an artery consist of three layers: an outer layer adventitia 101; a middle layer media 102; and, an inner layer intima 103. The adventitia is composed of connective tissues and elastic fibers, the media is made up of transverse elastic and muscular fibers and the intima has endothelial cells surrounded by longitudinal elastic fibers and connective tissue. The intima encloses passage 104 for blood flow. These layers thicken in the condition of arteriosclerosis. In addition, a calcifiedlike soft deposit forms between the intima 103 and the media 102. As a result, passage 104 is reduced thereby retarding or completely blocking the flow of blood. The present invention involves separating the media 102 from the adventitia 101 and extracting the clogging material from the artery.

FIG. 5 illustrates a portion of typical artery 100 having a main trunk 105 communicating with various branches 106, 109, and 111. The arteriosclerotic material, that is, the intimaand media. layers as well as any soft deposits between layers 103 and'102, tend to form in the trunk of the artery and extend intothe various branches. The arteriosclerotic material 107 is shown in FIGS. 5 and 8 as having spicules 108 projecting into the various branches. The physician shapes tip 72 (FIG. 1) of rod 70 to fit within the artery. Also a rod 70 and tip 72 is chosen having an appropriate size relative to the artery 100. Likewise, hole 71 can be shaped in accordance with the diameter of the artery. During use of the apparatus the loop 72 is located between the media layer 102 (FIG. 6) and the adventitia layer 101.

Thus, the arteriosclerotic material, namely the media and intima layers as well as the soft calcified deposits is positioned inside loop 72. Tip 72 is then oscillated by the converter 30 and motor 11 previously described and advanced slowly through section 113 by the surgeon applying forward pressure to rod 70. Actually, the arteriosclerotic core is not cut away from the adventitia but instead the adventitia is stretched away from the core which remains intact. The tip and rod is then backed out of the artery and the arteriosclerotic material is grasped and pulled out.

Set forth below is a description of the specific operative techniques for endarterectomization of the femoral artery, popliteal artery, anterior tibial artery and the posterior tibial artery.

The distal occluded femoral artery is exposed through the usual medial approach on the distal thigh, preferably opening the artery at the point where the popliteal artery is patent. The artery is opened through a longitudinal arteriotomy incision, and in opening the adventitia, a plane is established between the adventitia and the underlying core. The medial core is transected and if it is patent at this point, the distal intima would be handled by merely suturing the distal intima to the adventitia with 6-0 vascular silk suture to fix the distal intima. The core is then endarterectomized proximally for a distance of one centimeter. The core is passed through the loop of the instrument and the loop advanced to the point where the core is still attached. The end of the core is grasped with a hemostat 125 (FIG. 8) to stabilize the core as the loop is advanced and the machine is turned on and the loop advanced up the artery in the subadventitial plane. It is preferable to pass the loop approximately 4 to 6 inches and then pull it back, rotate the handle 180 and advance it again up the same path and then another 4 to 6 inches beyond. This process is continued up and down the artery until the endarterectomy is complete at the common femoral.

At the point of the common femoral the oscillating loop generally breaks through the proximal intima and the occluding core is removed intact. Pressure is then applied by external pressure over the common femoral at the groin and a debriding instrument 135 is passed into the artery. The debriding instrument 135 is identical to the device of the Dormia US. Pat. No. 2,943,626 with the exception that the catheter tube 136 is made of Teflon. The basket is expanded by merely advancing the distal guide wire to expand the basket and the basket is withdrawn in a rotating manner, such that the basket actually gently debrides the side of the adventitial tube, removing any debris that would remain. Frequently, the endarterectomy is so clean that nothing comes out with the debriding catheter; however, occasionally a fairly large segment of attached media is removed by the wire basket.

If the popliteal artery is occluded, the process is repeated down the popliteal artery as it was in the femoral artery. It is advantageous to dissect the arterial tree down to the trifurcation, isolating the anterior tibial, the peroneal and the posterior tibial and ascertaining whether or not these branches are open. Frequently, the anterior tibial may be occluded by spicule-like projections which can be removed leaving an intima attached, which can be sutured to the adventitial tube. This is true also of the peroneal. If the anterior tibial artery is actually occluded, then a proximal endarterectomy is accomplished for the first 1 to 3 centimeters of the anterior tibial artery, through the medial approach. The artery is exposed by an anterolateral incision thereby exposing the anterior tibial below the knee. A longitudinal arteriotomy is accomplished removing the proximal portion of the occluding core with a small wire loop 72 meeting the point of dissection started above. The instrument is then passed down the distal anterior tibial to the ankle. The anterior tibial at the ankle is exposed and a longitudinal arteriotomy performed to remove the core at the ankle. The posterior tibial artery is handled in the same manner by using smaller sized loops 72. These cores can be successfully removed from the distal vessels, anterior tibia] and posterior tibial. When cleaning out the peroneal artery, one has to remove this core very carefully because there is no distal control of the vessel. The small loop can be passed into the peroneal artery and the machine turned on and the loop advanced down the peroneal artery while holding the proximal core with the hemostat. At this point of no further advancement, withdraw the loop and the core that comes out, although it may not represent the entire core of the peroneal artery; even 3 to 4 inches of this artery opened frequently opens collateral vessels that otherwise would not be open.

The arteriotomies in the ankle of the posterior tibial and the anterior tibial are closed generally with vein patches; however, if the lumen is adequate the vessel may be closed with primary 6 or 7-0 silk sutures into the adventitia. The distal intima is attached as previously described in the proximal vessels. The arteriotomy in the popliteal artery is frequently closed primarily with a running suture of 6-0 vascular suture; however, if the lumen again is of questionable size a vein patch graft is indicated at this point. Arteriotomies in the superficial femoral artery are nearly always closed primarily without the use of vein patch grafts. It is important to know that in the endarterectomy of the anterior tibial and posterior tibial arteries, that the debriding catheter finds its most definite usefulness. In these smaller vessels frequently a considerable amount of debris is left. The wire debriding catheter is passed into these vesselsand the basket expanded. When the basket is withdrawn and rotated in the manner previously described, a considerable amount of debris is picked up and leaves a smooth adventitial tube, as a result of debridement with the wire basket.

One other point that may be a problem is in the endarterectomy proximally of the superficial femoral artery. If the core does not come out smooth and clean, and a good flow is not obtained, there may be a break off of the occluding core in the proximal end of the superficial femoral or the distal end of the common femoral artery. One would have to make the incision in the groin, exposing the common, superficial femoral and profunda arteries and deal with the plug remaining, either by the usual endarterectomy procedure, or by extending the oscillating endarterectomy instrument through the common femoral up into the ileac vessels.

It is important to perform postoperative angiography on the table at the time of the procedure to be sure that the adventitia] tube is actually clean and that there is no other occluding or partiallyoccluding segment of media or intima left in the tube. Even though a good pulse may be obtained distally, sometimes a portion of media or intima may be left behind and this can be readily determined by angiography and corrected at the time of the initial surgery.

It will be obvious from the above description that the present invention provides improved method and means for opening clogged arterial passages without cutting the clogging material from the artery or without destroying the clogging material by vibration. One of the advantages of the present invention is that the arteriosclerotic material will not wrap around tip 72 and tear since the tip is oscillated in lieu of being rotated. While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art.

The invention claimed is: 1. Apparatus for removing arteriosclerotic material from a body vessel comprising:

a rod having an axis and a proximal end and a distal end; a rotation to oscillation converter having an oscillatory output shaft connected to said rod and having a rotatable input shaft; an electric motor connected to said rotatable input shaft for moving said shaft about its axis;

and a looped tip secured to the distal end of said rod; and wherein: said converter includes a coupling pivotally mounted therein with a first slot and a second slot, said input shaft has a first projection mounted off center with respect to said input shaft and slidably received by said first slot, said output shaft has a second projection mounted off center with respect to said output shaft and slidably received by said second slot.

2. The apparatus of claim 1 wherein: said first projection and said second projection are spaced a distance at least greater than the width of said first slot and said second slot off center respectively with respect to said input shaft and said output shaft with said first projection and said second projection fitting snugly in said first slot and said second slot with one complete revolution of said input shaft causing said output shaft to oscillate through an angle of approximately 120.

sfrii 'fifiamms of claim 2 afii'fli'fiiii comprising: a flexible helical spring connected to and between said motor and said input shaft. 

